Photovoltaic modules can be secured to roofs, but the modules must be designed and mounted in such a way that they can withstand sufficiently high wind speeds. Furthermore, water can penetrate between the photovoltaic modules and, for example, corrode the mounts that secure the photovoltaic modules to the roofs. One traditional technique to waterproof an array of photovoltaic modules is to fit covers over spaces between the photovoltaic modules to prevent water from penetrating through these spaces. However, many of these coverings cause pressure differences between a cavity underneath the photovoltaic modules and the atmosphere. As a result of the pressure difference, high winds can more easily dislodge the photovoltaic modules from the roof and accordingly, the mounts and/or the photovoltaic modules for use on roofs need to be designed to be stronger and heavier to accommodate the extra forces created by the pressure difference.